It has been a sad bedrock of Connecticut's modern industrial history: As factory unions lose members, their political heft and bargaining power withers.

At Pratt & Whitney, the prime example, the ranks of Machinists union members in the jet engine maker's home state have thinned to 2,700, down by 700 in just the past three years, down from 11,000 in 1993.

Technology advances, recessions, local outsourcing and the movement of work to lower-cost places have turned the hourly Pratt workforce into just another labor group — far from its old perch as the keystone of Connecticut's metalworking might.

As the union and company negotiate a new contract with a Dec. 8 deadline, it's natural to think that the Machinists will gamely protest while the company continues to work its economic will. Some Machinists derisively say that this generation in the shops — averaging more than 58 years old — will be the last. The company's latest proposal, aimed at replacing 252 materials handlers and truckers with outside contractors, would knock the Machinists' rolls down below 2,500.

But there's another view emerging.

Even amid layoffs and the quiet darkening of machines, Pratt has poured $200 million into the factory floors of East Hartford and Middletown in the past five years — and plans to spend an equal amount in the next five. By 2016, the company expects to reach full throttle in its next-generation geared turbofan commercial engine program, and in the manufacture of F135 engines for the Joint Strike Fighter, which require significantly more hours of production work than the GTFs.

Middletown is one of several places where the GTF engine will be assembled, and it's the sole assembly site for the F135. The mile-long East Hartford complex, once a city within a town, is down to the core of the core, fewer than 1,400 workers. And although that's not a proud number, it appears to be at or near the bottom below which Pratt won't go.

Bingo! If Pratt is down to the number of workers it must keep at its hometown factories, and if the company faces a crucial transition to its new line of engines, the union suddenly enjoys renewed power at the bargaining table.

"It's not 'Happy Days are Here Again,' but it's enough for the union to stand tall," said Wesleyan University sociologist Jonathan Cutler, an expert on organized labor. "All they need to know is that they are going to be needed, and that's the basis of their leverage."

Cutler makes the point that unlike auto plants that vanished in the Northeast, taxpayer-funded defense work is backed by political power, so it can't disappear. I spoke with U.S. Rep. John Larson as he headed into a meeting Friday with Machinist leaders, and he vowed not only to pressure Pratt on the hourly workforce, but to find ways to sweeten the deal for the company.

When it comes to a strike, the ultimate show of force — last seen at Pratt in 2001 — it might seem unlikely for a group of workers making a base wage of more than $70,000 a year who are near retirement. Not unlikely at all, Cutler said, compared with low-wage workers still having to feed children at home. "If these guys can't strike, I don't know who can strike."

The union on Nov. 8 overwhelmingly gave the negotiating team authority to call a strike, a typical vote during talks, and both sides are preparing for a walkout just in case.

What does all this mean for the Machinists union, the much-watched standard-bearer for hourly workers everywhere? The company, seeing a dangerous negotiating adversary, is likely to offer up some added job guarantees for the upcoming three-year contract.

For example, if the union gives back the materials handler jobs — people who pack and move equipment and parts around the plants — and allows the company to bring in an outside contractor to do that work, Pratt certainly should agree to reassign or offer voluntary buyouts to the affected unionized men and women.

The union simply can't allow veteran workers to face layoffs to make way for nonunion replacements on the same shop floor. But well beyond that, Pratt might also agree, for example, to keep all geared turbofan parts and assembly work in place for at least the next decade, assuring a rare and coveted round of hiring to backfill retirements.

Finally in 2013, Cutler said, a Machinist might declare, "We're at a crazy low point historically, but we have found our footing."

That's not exactly how the Machinists portray themselves. "Brothers and sisters, it is crystal clear, management does not respect the bargaining unit in Connecticut," the union said in a pre-negotiation newsletter issued in August.

"They're so rich and powerful they can just get up and leave. They don't have to keep it at 2,000," said one longtime Machinist who asked to remain anonymous because the union has agreed not to talk publicly during negotiations.